Many common products, including plastics and detergents, depend on chemical reactions that rely on catalysts made from precious metals such as platinum. These metals are effective but costly and limited in supply. For years, scientists have been looking for alternatives that are cheaper and more sustainable. One promising option is tungsten carbide, a material abundant on Earth that is already widely used in industrial machinery, cutting tools and chisels.
Despite its potential, it was not easy to use tungsten carbide as a catalyst. Its chemical behavior can be unpredictable, which limits its wider adoption. Scientists led by Marc Porosoff, an associate professor in the University of Rochester’s Department of Chemical and Sustainable Engineering, have now made an important advance that could allow tungsten carbide to compete with platinum in key chemical reactions.
Why Atomic Structure Matters
According to Sinhara Perera, a chemical engineering doctoral student in Porosoff’s lab, one of the main problems lies in how the tungsten carbide atoms arrange themselves.
Tungsten carbide atoms can form many different configurations, known as phases, Perera says. These phases can strongly influence how well a material performs as a catalyst.
“There hasn’t been a clear understanding of the surface structure of tungsten carbide because it’s really difficult to measure the catalytic surface inside the chambers where these chemical reactions take place,” he says.
To solve this problem, the research team proposed a method to precisely control the structure of tungsten carbide during active reactions. In a study published in ACS catalysisPorosoff, Perera and chemical engineering student Eva Ciuffetelli ’27 manipulated nanoscale tungsten carbide particles inside chemical reactors that operate at temperatures above 700 degrees Celsius.
Using a technique called temperature-programmed carburization, the researchers created tungsten carbide catalysts in specific phases right inside the reactor. They then performed chemical reactions and analyzed which versions performed the strongest.
“Some phases are thermodynamically more stable, so the catalyst inherently wants to end up there,” Poosoff says. “But other phases that are less thermodynamically stable are more effective as catalysts.”
The team identified one phase in particular, β-W2C, that showed exceptional performance in reactions converting carbon dioxide into key building blocks for fuels and useful chemicals. With additional optimization by industry, the researchers believe this form of tungsten carbide could match the effectiveness of platinum without its high cost or supply constraints.
Conversion of plastic waste into new materials
In addition to carbon dioxide conversion, Porosoff and his collaborators also investigated tungsten carbide as a catalyst for recycling plastic waste. Their work focuses on upcycling, a process that transforms discarded plastics into higher value products rather than lower quality materials.
In a study published in Journal of the American Chemical Societyled by Linxao Chen of the University of North Texas and supported by Porosoff and University of Rochester assistant professor Siddharth Deshpand, the researchers showed how tungsten carbide can control a chemical process known as hydrocracking.
Hydrocracking breaks down large molecules into smaller ones that can be reused to make new materials. In this case, the team focused on polypropylene, which is used in water bottles and many other plastic products.
While hydrocracking is common in oil and gas refining, its application to plastic waste has proven difficult. The long polymer chains in single-use plastics are extremely stable, and contaminants in waste streams can quickly deactivate traditional catalysts. Platinum-based catalysts also rely on microporous structures that are too small for large plastic molecules to enter, limiting their effectiveness.
“Tungsten carbide, when made with the right phase, has metallic and acidic properties that are good for breaking down the carbon chains in these polymers,” says Poosoff. “These large, bulky polymer chains can interact with tungsten carbide much more easily because they don’t have the micropores that cause limitations in typical platinum-based catalysts.”
The results were startling. Tungsten carbide was not only much cheaper than platinum catalysts, but was also more than 10 times more effective at hydrocracking plastic waste. The researchers say this approach could open up new avenues for recycling plastics and developing a circular economy where materials are continually reused.
Measuring heat where it matters
A key factor in these advances is the ability to accurately measure catalyst surface temperatures. Chemical reactions either absorb heat (endothermic) or release heat (exothermic), and temperature control is critical to efficiency. Many industrial processes rely on multiple reactions occurring together, making precise temperature control even more important.
Current temperature measurement methods only provide rough averages that can hide critical variations on the catalyst surface. This lack of precision makes it difficult to fully understand and reproduce the catalytic behavior.
To solve this problem, the research team adopted optical measurement techniques developed in the laboratory of Andrea Pickel, a visiting professor in the Department of Mechanical Engineering. In a study published in EES catalysisdescribed a new method of direct temperature measurement inside chemical reactors.
“What we learned from this study is that depending on the type of chemistry, the temperature measured with this bulk data can be reduced by 10 to 100 degrees Celsius,” says Poosoff. “That’s a really significant difference in catalytic studies, where you’re trying to make sure the measurements are reproducible and that multiple reactions can be coupled.”
Using this technique, the team investigated tandem catalyst systems in which the heat released by one reaction drives another reaction that requires an input of heat. Better matching of these responses can reduce energy waste and improve overall efficiency.
Porosoff says the method could influence the way catalysis research is conducted more broadly, promoting more precise measurements, stronger reproducibility and more reliable results across the field.
Funding and support
The ACS Catalysis study was supported by the Sloan Foundation and the Department of Energy. The Journal of the American Chemical Society research received funding from the National Science Foundation. The EES Catalysis study was funded by the New York State Energy Research and Development Authority through the Carbontech Development Initiative.
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